Is it possible to control a three.js project?

the ultrasonic sensor would fire on the one who is closest?

Yes, that's right

What max. width/range can I expect?

I can't remember for sure but IIRC it's got around a 90 degree FOV and max distance of around 1.5m.

Some have datasheets which will tell you for sure: https://cdn.sparkfun.com/datasheets/Sens­ors/Proximity/HCSR04.pdf

That one says up to 4m, but I'm not 100% sure I trust it - that'll be if you're wearing a sandwich board :)

is the laser sensor ... working only on a certain width/range exactly in front of the sensor?

It depends on the sensor again - they usually say in the datasheet. IIRC the laser sensor is a bit narrower (30 degrees?) and maybe not as far away as the ultrasonic one though